Summary
The aim of this study was to determine the association between strength of the perioral muscles and masticatory performance. Subjects were 56 healthy adults (30 men and 26 women; mean age of ...24·9 years) with normal occlusion. Perioral muscle pressure was measured using JMS tongue pressure measurement device, and maximum tongue pressure and cheek pressure on the habitual chewing side (H) and non‐habitual side (non‐H) were measured. The masticatory performance was evaluated using gummy jelly, and the amount of glucose extracted was measured after chewing under condition H or non‐H. The association between sex and maximum tongue pressure was analysed using Student's t‐test. Cheek pressure and the amount of the glucose extracted between condition H and non‐H or between men and women were analysed by two‐way repeated‐measures anova. In addition, the correlations between maximum tongue pressure and cheek pressure on condition H, maximum tongue pressure and the amount of glucose extracted under condition H, and cheek pressure and the amount of glucose extracted under condition H were analysed using Pearson's correlation coefficients for men and women. The maximum tongue pressure, cheek pressure and the amount of glucose extracted were higher in men than in women. The amount of glucose extracted was higher under condition H than under condition non‐H, but no significant difference in chewing side was observed in cheek pressure between men and women. Additionally, positive correlations were shown between maximum tongue pressure, habitual‐side cheek pressure and the amount of glucose extracted on men and women. In conclusion, the association between higher perioral muscle pressure and better masticatory performance was shown.
Summary
The aim of this study was to investigate the effect of the tongue rotation exercise training on the oral functions using the measurement of maximum tongue pressure (MTP) and labial closure ...strength (LCS) in normal adults. In experiment 1, the differences in MTP and LCS at the measurement point for both groups with and without tongue rotation exercise training were examined. We instructed subjects to perform the tongue rotation exercise for 2 months. We measured MTP and LCS at the point before training and at the points of 1 and 2 months after the beginning of training. In experiment 2, the changes of MTP and LCS based on the sex differences and the measurement points in training were examined. We instructed subjects to perform the tongue rotation exercise for 3 months, and measured MTP and LCS at the point before training and at the points of 2 weeks and 1, 2 and 3 months after the beginning of training. The results of experiment 1 showed MTP and LCS increased with the progress of continuous training. The results of experiment 2 showed MTP and LCS were always higher in men than in women and increased significantly at 2 weeks of training in both sexes (P < 0.01). These results might be suggested that the tongue rotation exercise training was effective for the recovery of the activity of the stomatognathic system.
Gas breakdown caused by triboelectricity during friction between two insulators was observed in measuring two-dimensional spatial distributions of luminescence from gas discharge plasma. The ...insulators were chosen among diamond, quartz, sapphire, MgO single crystal, and quartz glass. The discharge between identical materials was also observed. The patterns of the gas discharge luminescence had a shape of a ring for all frictions between insulators. By using a gold-coated diamond pin for friction with a quartz disk, the discharge pattern differed from the ring pattern. In the case of insulator pin, electric field induced by a localized charge at the off-track area near the tip of the pin during friction accounts for formation of the ring shape of the gas discharge. The gold coating makes it possible to monitor an amount of charge transferred from the quartz surface during friction. The negative charge density at the frictional track on the quartz disk is calculated to be -2.2times10 -4 C/m 2 , which leads the gas discharge in a micro-gap near the contact between the diamond pin and the quartz disk.
Adsorption isobars of Xe and Kr on Ag(1
1
1) and Ag(1
0
0) were observed simultaneously by an extremely-low-current low energy electron diffraction and an ellipsometry in the temperature range ...between 60 K and 90
K and in the equilibrium pressure range between 8
×
10
−6
Pa and 2
×
10
−4
Pa. Two dimensional condensation of the first layer of Xe on Ag(1
1
1) occurred at the temperature 0.3
±
0.1
K higher than that on Ag(1
0
0). In the case of Kr on Ag(1
1
1) and Ag(1
0
0), the temperature difference was 0.2
±
0.1
K. This temperature difference was discussed on the assumption that it is caused by the repulsive interaction between the dipoles induced in rare gas atoms. We estimated the difference of the induced dipole moment
μ:
μ of Xe atom on Ag(1
0
0) is 6% larger than that on Ag(1
1
1) and
μ of Kr atom on Ag(1
0
0) is 14% larger than that on Ag(1
1
1).
Summary The purpose of this study is to clarify whether the state of occlusal contact on lateral excursion is related to the pattern of masticatory movement path. The masticatory movement during ...mastication of softened chewing gum and the occlusal contact on lateral sliding of the mandible by 1 mm (L1), 2 mm (L2) and 3 mm (L3) were recorded in 50 healthy subjects. The path of masticatory movement was classified into one of seven patterns. The number of teeth involved in the occlusal contact in each pattern was investigated and compared among different lateral occlusal positions. The occlusal contact was then classified into 15 types based on one or a combination of the following four regions; incisal region, canine region, premolar region and molar region. The number of occlusal contact type for each pattern was investigated and compared among patterns. The number of teeth involved in occlusal contact decreased as the degree of lateral excursion increased, and significant differences were observed among the lateral occlusal positions (P < 0·001). The occlusal contact tended to decrease in the molar region and increase in the canine or premolar regions as the degree of the lateral excursion increased. When comparing among patterns, significant differences were observed at L2 and L3 (L2; P < 0·001, L3; P = 0·030) but not at L1 (P = 0·318). The difference was remarkable at L2. It was suggested that the state of occlusal contact at L2 and L3, particularly at L2 was related to the masticatory path pattern.
The photon-stimulated desorption of (H
2O)
n
H
+ from water physisorbed on a rare gas solid (Ne, Ar, Kr, and Xe) has been investigated. From the measurements of the desorption yield as a function of ...the incident photon energy, the (H
2O)
n
H
+ desorption is effectively and indirectly induced by the multiple-excitation and -ionization of rare gas substrates. The direct excitation of the water molecule does not induce noticeable desorption of (H
2O)
n
H
+.
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